Lauren, who is 16 weeks pregnant, has claimed the ticket machine was broken and said she had the money and her card on her at the time

The letter states that failure to pay the full amount before Friday could result in an arrest warrant for her to appear in court or the fine could be increased by 50 per cent.

If the fine remains unpaid, Lauren could be sent to prison.

The 23-year-old from Barry, who now lives in Llanrumney in Cardiff, was travelling to work from a friend's house in Grangetown to Cardiff Bay.

She said she had the exact amount of money and her card on her, but the ticket machine was out of order.

The letter was sent to Lauren's parent's home.

She said: "I went straight down to get it and for them to show me such a high amount and giving me a few days to pay it is bang out of order.

"I'm 16 weeks pregnant and I have been trying to save for my baby. I've got lots of things to buy, fix my phone, bills, even trying to move into my own home, and it's made me feel depressed.

"I burst into tears. This just put so much pressure and caused me to have a complete breakdown. I've had nothing else from them, no phone calls, no nothing, just this letter that seems so threatening."

OFF THE RAILS

Lauren said she could not find a ticket collector on the first train to Cardiff Queen Street.

When she got on the next train to Cardiff Bay, she said she could see a ticket collector at the other end of the train, but was unable to make her way through the crowd because there was "just no room to move".

She added: "I knocked on the driver's door and no-one answered me and I had to quickly jump off because the doors were starting to close. I wasn't the only one, I remember there being a lady there as well and we were both looking for the ticket man at the same time."

In total, Lauren was fined £440 and ordered to pay costs of £130 plus a victim surcharge of £44 and £2.30 compensation.

Lauren received a letter about the fine from Cardiff Magistrates' Court

An Arriva Trains Wales spokeswoman said: "It is [customers’] responsibility to buy a valid ticket for the date and time of their journey. If ticket-buying facilities are available at the station they are travelling from, customers must buy their ticket before they board. If they are not available, they should buy their ticket from the conductor on board.

"It’s never been so easy to buy a ticket – in fact tickets can also be bought in advance from our website and on our smartphone ticket app."